Population and Predissociation of Vibronic States of Nitric Oxide

In a crossed beam experiment nitric oxide molecules are excited by electrons. From the observed emission of the γ bands ${\mathrm{(A}}^2{\Sigma }^{+}{\mathrm{\to \; X}}^2\mathrm{\Pi )}$ the mean electronic transition moment R̄_e and the population of the vibrational levels v′=0, 1 and 2 of the A ²Σ⁺ state are determined. The population numbers are compared with values calculated from kinetic equations. Relative rate constants are given corresponding to the transitions ${\mathrm{D\hspace{0.17em}}}^2{\Sigma }^{+}{\mathrm{,\hspace{0.17em}v\prime \; =\; j\; \to \; A\hspace{0.17em}}}^2{\Sigma }^{+}\mathrm{,\hspace{0.17em}v″\; =\; j}$ with j=1 and 2. From this it can be concluded that a predissociation occurs in the ${\mathrm{D\hspace{0.17em}}}^2{\Sigma }^{+}\text{,\hspace{0.17em}v′ = 2}$ state.